Loud speaker mounting



Aug. 29, 1933. F- p BARTLETT 7 1,924,591

LOUD SPEAKER'MOUNTING Filed Jam 30, 1932 13 a k l n in.

IHHHLUHHIM.

INVEN TOR.

fksosR/cx F. BARTLETT TORNEY.

Patented Aug. 29,. 1933 PATENT OFFICE LOUD SPEAKER MOUNTING Frederick P.Bartlett, Chicago, Ill., assignor to The Magnavox Company, Chicago,111., a corporation of Arizona Application January 30, 1932. Serial No.589,883 4 Claims. (01. 179-146) My present invention relates to loudspeakers such as are used with radio sets, phonographs and the like forreproducing sound and more particularly to a novel improvement whereby a5 loud speaker, its transformer and/or other accessories can beconveniently and securely mounted upon a panel or partition by a singlesecuring means.

The object of my invention is to provide a simple, inexpensive and novelform of mounting for a loud speaker.

Afurther object of my invention is to produce a loud speaker structurewhich can be easily and securely mounted upon any'bulkhead or otherpartition.

Another object of my invention is to provide a novel means for mountinga loud speaker beneath the cowl of an automobile body upon the thinsheet metal partition.

In mounting a loud speaker, of the type contemplated by my invention,upon a partition or the like it has been customary to recess the loudspeaker in the partition. This is generally accomplished by cutting alarge hole in the partition and securing the loud speaker to thepartition at its rim adjacent the periphery of the diaphragm. With sucha mounting it is necessary to use a. number of screws or other securingmeans at equally spaced points around the diaphragm and unless thepartition or baflie is relatively stiff and rigid the weight of thespeaker, which is greatest at a point some distance from the rim of thediaphragm, will have a tendency to break away from its support. It istherefore a further object of my invention to provide a securing meansfor mounting a loud speaker which will place the heaviest part of thespeaker close to the supporting partition and thereby greatly reduce thestrain upon the securing means.v This type of mounting willbe found ofparticular advantage in mounting loud speakers where the from combiningwith the sound waves emanating from the back of the diaphragm and thuscausing a distortion of the sound. Therefore, it may be said thatanother object of my invention is to provide a novel form of bafilemeans for a loud speaker which is not recessed in a partition or 5 othersimilar form of bafiie.

For a better understanding of my invention reference should be had tothe accompanying drawing wherein I have shown by way of illus trationand not of limitation preferred embodiments thereof.

In the drawing wherein like numerals refer to like parts throughout theseveral views;

Figure 1 is a vertical view partially in section showing one form of myinvention,

Figure 2 is a view similar to Figure 1, showing another form of myinvention,

Figure 3 is a vertical view showing my improved bafile in section,

Figure 4 is a fragmentary view partially in section showing the mannerof mounting a loud speaker in an automobile in accordance with myinvention, and

Figure 5 is a modified form of my invention.

In the drawing 10 designates a magnetic field frame of pot likeconstruction. The frame can be of any shape. It is illustrated in theform most commonly used. The frame 10 carries the usual annular polepiece 11 to which there is attached a diaphragm housing or support 12. Aconical diaphragm 13 which is secured at its rim to the support 12 hasan actuating coil at its apex that is disposed in cooperating relationwith the magnetic field structure.

Within the frame 10 there is provided a central or inner pole piece 14.One end of this pole 5 piece 14 is disposed in spaced relation with anopening in the pole piece 11 to provide an annular air gap in which thediaphragm actuating coil is located. The other end of the pole piece 14is usually projected through the frame 10 and riveted or peened over tosecure it in place.

In the past, in a mounted speaker of the above type, it has been thepractice to secure the loud speaker at the rim of the housing 12 to asuitable supporting baflle. j

This form of mounting is very satisfactory in radio cabinets, etc, wherethe apparatus is not subject to any substantial amount of vibration orjarring but when a mounting of this character is used it has been foundnecessary, particularly with a large speaker, to provide an additionalfoot or support at the back of the field frame 10 in order to relievethe strain upon the securing screws which engage the bafile;

It is well known that the heaviest part of a dynamic loud speaker is thefield frame. In loud speakers of this type it is customary to mount theinput transformer upon the field frame and this practice further adds tothe weight of. the speaker at this point. This heaviest part of no i thespeaker, due to the depth of the cone, is located some distance from therim of the diaphragm and support and as a result the heavy weight of thefield magnet and transformer tends to pull the diaphragm housing awayfrom the supporting baffle, unless a support or foot is placedthereunder as suggested above.

There are also installations in which it is impractical to mount a loudspeaker where the supporting partition can act as a baffle. Sometimes itis impossible to cut a large enough opening in the partition and atother times the particular partition is not suitable for' this type ofmounting. An example of this latter case is where it is desired to mountthe speaker upon the bulkhead which divides the engine compartment fromthe body of an automobile. The bulkhead referred to is usually of thinsheet iron which is not sufficiently rigid to properly support thespeaker. An objection to the prevailing form of mounting in this latterposition is also due to the fact that it is not good practice to exposethe speaker to the grease and oil which usually collects under the hoodof an automobile.-

In one embodiment of my invention, in order to overcome the aboveobjection, I provide the field frame with a centrally disposed threadedstud 15 which extends rearwardly so that it may be projected through thepartition 17 to secure the speaker thereupon.

In Figure 1 of the drawing the stud 15 is shown as threaded into the endof the innerpole piece or core 14 and in Figure 2 the stud 15 isillustrated as formed integrally with the core 14. The stud 15 isthreaded on its end and a nut 16 is threaded thereupon so that when thestud is projected through a partition 1'1, as shown, the speaker can befirmly clamped in place.

Cooperating with the stud 15, as illustrated in the above figures of thedrawing, there is provided between the frame 10 and the partition 17 arelatively large washer 18. This washer 18-may be made of wood, fibreor'other yielding material which will compensate for any irregularityin' the surface of the frame 10 or partition 17 and afford a firmengagement.

A second relatively large washer 19 is also supplied when the partition1'! is of thin flexible material. This washer serves to stiffen thepartition at this point and prevents a bending thereof under the weightof the speaker.

It is appreciated that this form of mounting does not permit thepartition 17 to act as a baflle for the diaphragm 13 and therefore someother form of baflle must be provided. The baflles now most commonlyused with this type of speaker project out from the rim of the diaphragmin a plane at right angles to its axis of movement.

As suggested above. it is impractical to mount a baille of the abovetype under the cowl of an automobilev body and many other like pointsand therefore I provide a novel baflle which can be disposed around thespeaker in an effective manner.

In Figure 3, I show one type of ballle which can be formed by acylindrical member 20 secured to the rim of the speaker support 12 so asto project rearwardly of the diaphragm and terminate in spaced relationwith the partition 17. While this baflle member 20 is illustrated ascylindrical, it is to be understood that it may take other shapes, forexample it may be square or conical in form.

In connection with this form of baflle it should be stated that othershave mounted dynamic waves and prevents the efficient operation of thespeakers in a box and then secured the box upon the partition. Such anarrangement seriously interferes with free movement of the air from therear of the diaphragm, sets up compressional speaker. The presentarrangement distinguishes from the above practice in that the baffle iscompletely out of contact with the partition 11'! and therefore affordssuflicient freedom for the movement of the air at the rear of thediaphragm.

In this figure of the drawing the speaker frame 10 is shown as carryingan input transformer 21 and a terminal block 22 upon which the ends ofthe several conductors of the speaker terminate. The terminal block 22is shown as provided with a protecting cover 23.

A further modification of my invention is illustrated in Figure 5 of thedrawing. In this embodiment I dispense with the stud 15 and project thepot like frame 10 through the partition 17. The frame 10 is then securedin place by screws 24. With this form of mounting the weight of thespeaker is practically balanced on the partition. This arrangementbrings the rim of the diaphragm support 12 nearer the supportingpartition 17 and therefore, in order to provide additional air spacebehind the diaphragm I may, if necessary, provide a conical baiile 25,as shown.

From the above description it will be clear that, in addition toproviding a new and novel mounting, I have provided a mounting for loudspeakers of the electro-dynamic type which will bring the parts of thespeaker of greatest weight near the point of support. This arrangementcompletely eliminates the possibility of the speaker being dislodgedfrom its mounting when subjected to any vibration or violent jolting. I

While I have, for the sake of clearness and in order to disclose myinvention so that the same can be readily understood, described andillustrated specific devices and arrangements, I desire to have itunderstood that this invention is not limited to the specific meansdisclosed but may be embodied in other ways that will suggest themselvesto persons skilled in the art. It is believed that this invention is newand all such embodiments as come within the scope of the appended claimsare to be considered as part of this invention.

Having thus described my invention, what I claim and desire to secure byLetters Patent is- 1. In an electro-dynamic loud speaker suitable formounting .upon a vertically disposed partition, the combination of anelectro-magnetic .field frame having a diaphragm mounted Pupon one endthereof, a single stud extending rearwardly from said field frameadapted to project through the partition, a yielding member between thespeaker frame and one side of the partition, a relatively large washerof stiff material on the other side of the partition, and means upon theend of said stud for securing said yielding member and said washer inclamping engagement with the partition to thereby secure the speakerthereupon.

2. In a loud speaker of the electro-dynamic type having a conicaldiaphragm, the combination of a means upon the speaker framefor securingit against a surface with the diaphragm projecting outwardly therefromso that said surface will not act as a bailie, and a truncated conicalbaille secured at the rim of the diaphragm projecting toward and held inspaced relation with said surface.

field frame, a conical diaphragm mounted in operative relation upon oneend of said field frame, means carried by said field frame for securingit against a non-baflle forming surface, and a truncated conical bafllemember secured at the rim of said diaphragm and projecting rearwardlyover the diaphragm with its free edge out of contact with saidnon-baflle forming surface.

FREDERICK P. BARTLETT.

